In order to realize 5G goals such as increase of mobile data flow in each area at 1000 times of speed, increase of throughput of each user at 10 to 100 times of speed, increase of the number of devices connected by each user at 10 to 100 times of speed, increase of battery service life of low-power devices by 10 times and decrease of end-to-end delay by 5 times, some new wireless technical solutions must be put forward in 5G.
At present, Ultra-Dense Network (UDN) is an important means to achieve the first two indexes of 5G. The key technology of UDN is to enable a great number of nodes to coexist in a homogeneous or heterogeneous way in a dense region. Since ultra-dense deployment causes very serious interference between cells, a capacity of each area is impossible to linearly increase with the number of nodes in this area. In addition, when User Equipment (UE) moves between cells, a great amount of switching is caused. Ultra-dense deployment brings about a tough challenge to mobile signaling load and mobile robustness.
In the related art, in order to solve the problem existing in mobility, new concepts have already been put forward, e.g., virtual cells such as soft cell and phantom cell. A soft cell or phantom cell consists of a macrocell and microcells with best communication quality in neighboring cells of the macrocell. In a process of movement, UE only needs to change a microcell in the soft cell without being switched between microcells.
However, in the related art, if UE is not in the coverage range of the macrocell, a virtual cell cannot be realized.